A DOS is a standard specification of middleware for data-centric publish-subscribe communication between distributed application programs and has been standardized in an object management group (CMG). The DDS generally includes a domain which is a shared area and domain participants, and the domain participants are classified into publishers and subscribers for each datum. In one domain, a plurality of publishers and subscribers exist and exchange samples of topics having a predetermined data type.
The structures of existing DDS products are generally classified into a decentralized structure and a federated structure. The decentralized structure is a structure in which each of DDS applications of one node has a data-centric publish-subscribe (DCPS) layer and a real-time publish-subscribe (RIPS) layer and performs a DDS service. This structure has advantages in that a small number of DDS applications are driven and operate without a separate daemon but has disadvantages in that a process of developing the DCPS layer and the RTPS layer is complex and problems may occur in discovery in the case where a lot of nodes participate in the DDS domain. The federated structure is a structure in which individual DCPS layers commonly use a daemon type RTPS layer. This structure has less complexity than the decentralized structure and is more appropriate for a large-scale system. However, the federated structure incurs additional inter-process communication expense and a problem of the daemon type RTPS layer influences the whole system.